In recent years, image pick-up apparatuses using solid-state image pick-up device such as digital still camera, etc. are being popularized. With popularization of such digital still camera, realization of higher picture quality is required. Particularly, in digital still camera having a large number of pixels, etc., photographing (imaging) lenses excellent in image formation performance, particularly zoom lenses, which comply with solid-state image pick-up device having a large number of pixels are required. Further, there also exists demands for miniaturization, and particularly zoom lenses in which realization of thin structure in the camera depth direction is attained are required.
For example, as a zoom lens which is compact and is excellent in image formation performance, there conventionally exists a three group zoom lens consisting of a negative first lens group, a positive second lens group and a positive third lens group in order from the object side as described in the Japanese Patent Application Laid Open No. 2002-350726 publication. In the optical system disclosed in this publication, length of the optical system lens total thickness is limit as thickness in the camera depth direction at the time of sinking barrel so that it cannot be said that miniaturization in the camera depth direction is sufficient.
On the other hand, there is known a zoom lens in which prism is inserted between lenses to thereby bend or fold the optical system so that miniaturization in the optical axis direction has been further promoted. For example, as described in the Japanese Patent Application Laid Open No. 1996-248318 publication, the optical axis is bent or folded by using prism within four group zoom lens optical system consisting of a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group in order from the object side to thereby realize miniaturization in the optical axis direction. In the optical system described in this publication, front (optical) gem (front lens element) and reflection member are large so that miniaturization is not sufficient.